Hello and sorry to hear your wheel got stolen.
First consideration to make is whether you will be buying a second hand wheel with the cassette already fitted or buying a wheel and cassette separately. If you are buying the wheel with the cassette already on it, then you only need to worry that the wheel fits your frame and cassette works with your derailleur. If you are buying them separately then you need to also worry about hub to cassette interface.
Anyway, here we go. Things to consider in no particular order.
Wheel to frame compatibility
You wheel will need to have the right diameter. As you stated you have 700 wheels, so look for a 700 wheel to replace it. Smaller wheel will also fit but will look rather comical if you keep your original front wheel.
You wheel will also need to have the correct interface to fit the frame. Could be quick-release or through axle. Check your frame, identify the type, go with the right one.
Your new wheel will have to be designed for correct type of brakes (Disk/Rim). Note that these are not cross-compatible. Do not attempt to use disk brake wheels with a rim brake bike.
Last but not least your wheel will have to have correct size/spacing to fit your frame chainstays. This is important to get right and is whole subject in itself. For your convenience: AASBHTA
And finally it is a bonus if you can get hold of a wheel with similare rim width (inner/outer) to your front one. This will save you the hassle of fitting matching tires to front/reare wheels in the future. Note that rim width does not have to exactly match between front and rear wheel, it just has to be close within few mm.
Hub to cassette compatibility
This is only relevant if you are buying the cassette separately
There are currently three most commonly used interfaces: Shimano Hyperglide, Shimano Microspline and Sram XD. There are others but your are unlikely to come across them if you are looking to match a Tiagra... Check specifications online, go with the correct interface.
For compelteness I will mention that there is a consideration of hub width and how wide of a cassette it can accommodate. This is specific to Shimano Hyperglide. Some hyperglide hubs will only fit up to 10 speeds and will not fit 11- or 12-speed cassettes. This should not be a concern for you.
Cassette to derailleur compatibility
First and foremost, your new cassette must be 10-speed if you want to keep your old derailleur and shifter working correctly. No exceptions on this one.
Mixing cassettes from different manufactureres is a minefield. Up to 9 speeds you could safely mix shimano and SRAM, but from 10 onwards it gets progressively worse. I would recommend sticking with Shimano 10-speed cassette or looking for an aftermarket cassette (Sunrace or similar) that has a reputation of working with Shimano 10-speed derailleurs.
Last thing to consider is the size of your derailleur cage and its ability to accomodate largest cassette cog. This is not an issue if you are swapping like for like, but can become a problem if you try to stick an MTB cassette onto a bike with short cage road derailleur.